ABSTRACT
Biological. probes. are. indispensable. tools. for. studying. biological. samples,. cells. in. culture,. and. animal.models..Exogenous.probes.are.frequently.multifunctional,.having.one.component.that.can. detect.a.biological.molecule.or.event,.and.another.component.that.reports.the.presence.of.the.probe.. A.fundamental.example.of.this.functionality.is.a.fluorescently.labeled.antibody:.when.administered. to.a.monolayer.of.fixed.cells,.the.antibody.binds.to.its.target.molecule,.and.the.fluorophore.emits. light. to. signal. its. presence.. Of. the. many. available. reporters. (e.g.,. radioactive. isotopes,. chromophores,.and.fluorophores),.fluorescent.molecules.have.been.found.to.be.invaluable.due.to.their.inherently.high.sensitivity.of.detection,.low.cost,.ease.of.conjugation.to.biological.molecules,.and.lack.of. ionizing.radiation..Indeed,.organic.fluorophores.and.fluorescent.proteins.have.been.used.in.nearly. all.avenues.of.biological.sensing,.from.in vitro.assays.to.living.animal.imaging..Recently,.quantum. dots.(QDs).have.been.developed.as.a.new.class.of.biological.fluorophore..With.easily.tunable.properties.and.significant.spectral.advantages.over.conventional.fluorophores,.QDs.have.already.been. used.for.ultrasensitive.biological.detection.
